In recent years, further improved reliability and loss reduction have been required of devices including a semiconductor device such as a power device. With this trend, power devices such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), a JFET (Junction Field Effect Transistor), and an IGBT (Insulated Gate Bipolar Transistor) have been required to have a higher reverse breakdown voltage and reduced on-resistance.
To meet these requirements, an ACCUFET (Accumulation Mode FET) has been proposed in which a plane shape of a cell (i.e., plane shapes of a body region, a carrier supply region surrounded by this body region when viewed two-dimensionally, and the like) is hexagonal, with each cell being arranged to be positioned at a vertex of the hexagon. With such arrangement, a reverse breakdown voltage can be improved (see WO02/43157 (Patent Document 1), for example).